Preliminary studies for the long-term in vitro conservation of vanilla (Vanilla planifolia A.) germplasm.

Marali García-Castillo*, M. T. González-Arnao**, Y. Martínez-Ocampo*, R. Gámez-Pastrana* and Claudia Lázaro-Vallejo**

Universidad Veracruzana, Campus Córdoba-Orizaba, Veracruz, México.

* Facultad de Ciencias Biológicas y Agropecuarias, CP 94500, Apartado Postal 177,

Córdoba.

** Facultad de Ciencias Químicas, Prol. Oriente 6, No. 1009, CP 94340, Apartado

Postal 215, Orizaba. E-mails: mtgarnao@ivia.es

Mexico is the center of domestication of vanilla, as much as the country with the largest genetic diversity of Vanilla planifolia compared with other vanilla-producing countries. However, today, wild populations of vanilla are considered threatened by extinction, and because vanilla is exclusively propagated from cuttings, the collecting of stem cuttings also progressively lead to the arrest of growth and development of the mother plants. Cryopreservation is the storage of biological material at ultra-low temperature, usually that of liquid nitrogen (-196°C). Nowadays, cryogenic techniques offer the only safe and cost-effective strategy for the long-term conservation of species vegetatively propagated. In addition, they are also becoming an important tool for in vitro conservation of endangered germplasm. Some preliminary experiments have been initiated in order to guarantee the cryopreservation of vanilla germplasm. First step involved the creation of an in vitro plant collection using explants of Vanilla planifolia. At present, the in vitro cultures obtained are serving as mother material for the isolation of meristems and calli production. For in vitro induction, it was studied the effect of two types of explants: axillary buds and nodal segments containing each one an axillary bud. The disinfecting solutions, sodium hypochlorite or mercuric chloride were also applied at various concentrations and treatment times. Current research towards cryopreservation is focused on the encapsulation of meristems in 3% calcium alginate, and on the influence of pre culture at high sucrose concentrations on viability of alginate-coated vanilla tissues.